At first the white cardboard coasters underneath the glasses at Sparrow don't look like anything special. But run your fingers over the surface and you'll feel the outlines of a little embossed birdcage, white on white, with two of the bars pried apart. That's the symbolic hole that allows the sparrow to fly free.

It's the kind of keen visual detail that has marked chef Monica Pope's trendsetting Houston restaurants for two decades and counting now: from the Quilted Toque to Boulevard Bistrot to t'afia, Sparrow's predecessor in this selfsame Midtown space.

Last summer, Pope closed down t'afia, did a quick remodel and reopened as Sparrow Bar & Cookshop. She needed a change, she indicated in interviews at the time, and she got it. She has shed her old cage. Gone is the cool, aloof Zen of t'afia's lovely dining room. Sparrow is all raw industrial warmth, with ceiling girders and shaggy black insulation on display, tables and chairs of custom black metal, lanterns made from oxidized mesh pizza pans.

Shots of scarlet in the form of oversize, asymmetrical wing chairs dot the room, a sinuous slab of wood forms a community table in the bar area, and a rear service station, shelves lined with dishware, makes a practical still life that is pure Pope. Even the soundtrack pulses to a different, younger beat, with Imagine Dragons and the Lumineers threading through rap, electronica and an occasional old antihero such as Johnny Cash or Neil Young.

So the slender, boxy space doesn't feel like the calm temple of university dons and museum trustees anymore. But Sparrow tastes familiar. The reworked menus show off Pope's love of local garden ingredients and her trademark Mediterranean style, tweaked with Asian touches.

The march of the seasons still animates the menu, but now Pope's changes arrive at a brisker pace. So the Bison Bolognese you love on Thursday - its meaty savor lifted by the lemony, garlicked perfume of gremolata, its bed of hand-cut sweet-potato noodles as earthy and springy as spaetzle - may be gone by Saturday. Grab that pillowy-tender veal cheek while ye may, for tomorrow its voluptuous cushion of polenta may show off something completely different.

And what's this? There's a burger, and a great one - with big beefy Longhorn flavor, a house-baked bun and lively condiments - available from lunchtime all the way though the afternoon until closing time. And there's breakfast on Saturday: beautifully made scones flecked with lavender buds and apricot, with a tangy blob of creme fraiche to heighten the luxury; crisp slabs of applewood-smoked bacon; eggs with a coarse house-made beef sausage that's alive with red pepper.

That's right. Pope, famous for her refusal to open for anything but dinner and the occasional Friday lunch, is open all day, continuously, from 10 a.m. to midnight. Ironically, she had her public so well trained that they don't seem able to get their heads around her new, looser attitude and hours. Eight months into the Sparrow incarnation, lunches and Saturday breakfast remain underpopulated. They shouldn't be.

A nice little "bar bite" menu is available when lunch or dinner is not being served, and it ranges from that Longhorn beef burger with cornmeal-fried onions to Pope's classic chipotle hummus. Lately Pope has been doing a series of rillettes that taste like they were put up in jars by grand-mère herself. A chopped chicken-heart version was pure simplicity and earthiness under its sunny layer of fat; and when my server described a recent version made of beef tongue with guajillo chiles, I realized that grand-mère had gotten one of those reality-show makeovers.

Those rillettes may be on Sparrow's separate bar-bites menu, but with a buttery pile of garlic toasts, they're a great appetizer to share. That's the thing about the restaurant's format: Like so many ambitious new restaurants these days, it takes some getting used to. You have to know to include the bar-bites menu in your planning; and you have to discover that many of the "Apps to share … or not" are the size of small or medium-size entrees.

The Bison Bolognese that wowed me at $15 was plenty of dinner for one. Adding Pope's spectacular Kale Caesar salad as an unconventional dessert was almost too much. Or it would have been, had the garlicky slide of avocado dressing not been so irresistible against the crunchy frills of kale. White anchovy fillets and just the right touch of Parmesan shavings chimed in to make this one of the finest salads in the city.

Thinking about that salad, I found myself admiring the way Pope has pared back her vision over the years, simplifying her cooking in a way that seems almost Italian in spirit. What seemed like a growing austerity a couple of years ago now tastes more like purity and assurance.

Her seasonal vegetable sides - available singly or as a satisfying dinner plate of three for $18 - seem more authoritative than ever these days. Crisped brussels sprouts pop with mustard seeds and red miso. Hearts of baby red cabbage glazed with tart-sweet balsamic vinegar are soft without, near-meaty within, fleshed out with caramelized onion and pecans.

Roasted baby beets with a beet-green-and-celery pesto taste like the essence of late Houston spring, right down to the pleasantly murky taste of the wilted beet greens alongside. And the green peas "cacio e pepe" style, like the classic Italian pepper-and-cheese pasta dish, are tiny miracles of intensity, roughed up with aromatic black pepper and then soothed with butter. Who needs noodles when you have peas like these?

I've always liked Pope's soups, and that continues: with a thick, burnished-ochre cauliflower and leek potion one night; and with a deeply gratifying beef-tongue and heirloom bean soup served at a recent Saturday breakfast, garnished with delicate tortilla strips and cilantro flowers, a smart riff on menudo.

Sparrow's "Center of Plate" dishes, which fill the function of entrees and are based on traditional fish and meat proteins, often strike me as the least interesting part of the menu, with a somewhat dutiful feel to them. There's usually a steak selection - it was an interesting cut called "spinalis" on a recent evening, dense and intense and neatly squared off - with a caramel miso treatment that was simply too sweet for me. Another night I ordered a duck confit plate and was given the chicken confit instead, a large appetizer portion of dry, stringy bird that left me feeling I had wandered into a completely different restaurant. It was too late in the evening for me to want to switch it out, and by then I was understandably confit-shy.

For diners who want the reassurance of familiar dishes, Pope still offers her standby flattened chicken with salsa verde, and I have had excellent luck with the fish of the day (pristine king mackerel on an early visit) accented North African-style, with chermoula or preserved lemon-and-date marmalade.

But along with such staples sits a nightly vegetarian entree that has been good each time I've tasted it, from a risotto-style dish of farro grains cooked with coconut milk, shallots, beets and fennel, to a complex stew of curried barley and lentils. One senses that this is where Pope's heart lies these days.

Indeed, when my dining companion on a recent evening told Pope she had given up eating meat, Pope's eyes lit up. "So have all my best friends," she said. They both looked at me expectantly, joking that I was a holdout.

I'm not there yet, but I like the trend to a more vegetable-based diet, and I eat that way at home. I suspect that Pope is on a leading edge as she ventures further along that path, just as she has been with so many things in Houston, whether it be contemporary restaurant design or sourcing ingredients locally or promoting and organizing farmers markets.

Her all-Texas weekly tasting menus that seemed like such a breakthrough in 2004, when t'afia was young, now have equivalents all over town. Ambitious young chefs and new restaurants are doing things as a matter of course that Pope pioneered here. Everyone else now trumpets the provenance of their ingredients while Pope, who led the way, has given it up entirely.

That seemed like part of Pope's frustration last summer when she announced her plans to scuttle t'afia in favor of something different. A new wave of Houston restaurants was generating all the heat.

So Sparrow is aimed at a younger, looser audience, and Pope has succeeded in luring them in. A weekend night is liable to be jammed with young women in tight bandage dresses, shirtsleeved bros laughing up a storm, couples bent together at a couple of cozy tables tucked to the sides of the bar. It's a crowd that is much more diverse than it used to be.

They pile into the two big community tables, inside and out on the patio. They cluster at the bar, drinking carefully considered cocktails or wines from Pope's utterly personal, frequently surprising list.

They eat well, too, and interestingly. Aside from that dismal chicken confit and an early-days order of overcooked sweetbreads, my food over a half-dozen visits has been consistently good, with just a few uneven spots.

A sausage-and-scrambled egg biscuit breakfast dish bore a red-onion gravy that lacked the depth and savor I had been expecting. A clever avocado "sashimi," velvet-ripe slices with a garlicky almond sambal that seemed wildly brilliant on one occasion - sparkling with fish sauce and pinpoint bursts of red pepper and sweetness -turned unexpectedly subdued the next time out, pleasant but undistinguished.

But when that avocado sashimi was good, it soared. So, when the kitchen is percolating, does Sparrow.